Manchester United manager Sir Alex Ferguson believes any one of six teams could win the Barclays Premier League this season.

Ferguson is not prepared to write off any of the traditional big four, even though Arsenal have endured a miserable summer, with question marks remaining over the futures of star men Cesc Fabregas and Samir Nasri, and Liverpool are without a championship since 1990.

And, with Manchester City preparing to make a concerted challenge on top spot and Ferguson believing Tottenham will benefit from being out of the Champions League, the United boss feels it will be a tougher title race than ever this season.

"We used to talk about a top four, with ourselves, Arsenal, Chelsea and Liverpool," he said.

"You can't say that any more.

"Manchester City have definitely come into the frame. They have a buying power better than the rest of us.

"Maybe having the run in the European Cup just stretched Tottenham too much last season and they ended up being out of the top four.

"But you look at those teams and say any one of them could win the league."

United will face them wearing a distinctive new black and blue hooped away kit, which will be unveiled in Seattle later today.

Inspired by the 1948 FA Cup final and 1968 European Cup final shirts, the new away kit is made from Nike's ground-breaking recycled polyester.

Each complete kit is made up of up to 13 reclaimed plastic water bottles, which is said to reduce energy consumption by up to 30%.

New boys Phil Jones and David de Gea will link up with their new team-mates for the launch, with Danny Welbeck and Tom Cleverley also making a belated return after Under-21 duty at the European Championships.

Ferguson has confirmed none of the quartet will be involved against the well-supported Seattle Sounders in the second game of United's tour on Wednesday - part of a vital preparation for what lies ahead.

"We know it is going to be such a big challenge again this season," said the Scot.

"It never changes. It is not an easy league to win. But we have experience of winning it. That helps."